Toyota: acceleration noise, steep incline, oil level

Question
Hello,
I have a '97 Rav4, great car, "only" 72k miles. But lately when I go to accelerate hard, i.e. pass cars on a highway, or climb a steep incline, I hear a funny, tinny kind of noise (sounds **something like** you'd hear if you had lug nuts rattling around under a hubcap). The noise seems to come from the engine area.
It is an acceleration issue (ie carbureator)? Fuel injector? Maybe spark plugs?
What do you think?

Answer
Hello,

did you change oil lately? Did you check if the oil level is at his maximum?
This looks like tickling valves when you have low oil level, or wrong kind of oil...

.. but it's difficult to say without hearing the noise. Maybe it's only something rattling at full gas..
Check the oil and then let me know!

Regards,
Jack